We present several methods for implementing optimal HDSL2 transmit spectra that, at activation, adapt to the surrounding interference and noise. The methods are based around either a set of fixed transmit filters or a single adaptive transmit filter that uses the optimal transmit spectrum. Designing optimal spectra with minimum required power can further increase the spectral compatibility of the system. Transmit spectrum can be adapted on-line to changes in intereference characteristics desired margin is reached (power control). Adaptation of transmit spectra to intereference and noise could be made an option in the HDSL2 standard.